scanner.c: store to misaligned address

# <<BUILDDIR>>/knot-dns/src/zscanner/tests/tmp/25_SOA.in
scanner.c:6097:4: runtime error: store to misaligned address 0x7f94866bf512 for type 'uint32_t' (aka 'unsigned int'), which requires 4 byte alignment
0x7f94866bf512: note: pointer points here
 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00
              ^ 

This is in the generated code, so dunno what are our capabilities of fixing it.